Answer: The exact times have been calculated for the centre of Stonehenge for 2011 and can be found at the
link below. Our thanks to www.visit-stonehenge.com for supplying the data.
Latitude 51°10'43.99'N Longitude 1°49'34.24'W For the Centre of Stonehenge
Sunrise and Sunset Calendar for 51°10'43.99'N 1°49'34.24'W .Times need to be adjusted for BST